Topotecan–loaded niosomes: Characterization and pulmonary drug deposition in treating lung cancer

Aim: To examine the stability, physicochemical properties, and cytotoxic efficacy of TPT-loaded niosomes on non-small cell lung cancer (H460 and A549) and assess in vitro drug deposition.Material and Methods: TPT-loaded niosomes were prepared using hot melt emulsification and homogenization.Cytotoxicity was evaluated using clonogenic cell survival assays on H460 and A549 cells.TPT-loaded niosomes and TPT solution were nebulized for 1.20 minutes using a mesh nebulizer (Aerogen), with drug deposition and aerosol particle size distribution assessed via a Next Generation Impactor.Results: TPT-loaded niosomes achieved an entrapment efficiency >76%, with particle sizes of 1191-1264 nm and zeta potential from -51 to -46 mV.TPTloaded niosomes showed greater cytotoxicity than TPT solution, inhibiting H460 cell survival by 51% versus 31% (p < 0.0001) and A549 by 49% versus 38% (p < 0.001).The niosomal formulation also demonstrated higher drug deposition (FPF% 49.34%; 87.07 g) compared to the TPT solution (36.41%; 60.04 g).Discussion: Niosomes, as non-ionic surfactant vesicles, offer an effective delivery system for hydrophilic drugs like topotecan (TPT), encapsulating it within aqueous layers to enhance stability and therapeutic efficacy.This study demonstrates that TPT-loaded niosomes provide higher cytotoxicity against lung cancer cells and improved deposition of respirable particles compared to TPT solution, highlighting their potential as targeted pulmonary drug carriers for lung cancer treatment.